91 Cherokee hesitation and low idle

I know nothing about cars so please be elementary in your replies...
4.0 4X4 with 233K miles, orig engine replaced at 118K
Was running hot. Had new radiator installed. Temp is now fine but since the work was done can be driving, step on gas and get no acceleration. After a few seconds, kicks in. At stop, idles very low, feels like will stall, will idle back up and feel like the car is shifting. Mechanic has not been able to solve problem. Help! Would like to get a few more years out of this Jeep.

i had a similar problem, now when you try to accelerate does it feel sluggish and does it back fire or feel like it is skipping a cylinder?

this sounds like a fuel delivery problem, replace your fuel filter first. like 8 bucks. now i had a very close problem, your best bet is replacing the fuel pump if the fuel filter is not the problem.....not hard at all. dont spend money on like TPS, CPS, MAP, or any of those sensors till you try the filter,then pump......i tried the sensors first and wasted $350. best of luck!

There is no way your mechanic did anything while changing radiator. Unless it is the temp sensor was damaged in the works. Has you mechanic checked that?

It does backfire and then the acceleration will kick in.

Try unplugging your MAF (Mass Air Flow) Sensor. It is located on your throttle body. Or you may have a MAP Sensor. Either way it is located in that spot. And if this is the problem is will usually clear up if unplugged. It does need to be replaced though either wise it will cause poor fuel economy. This is a very common symptom of these 2 components.